Oral gene therapy for hypoparathyroidism: A rat model

The use of nonionic polymeric micelles orally to protect and deliver plasmid DNA in vivo was investigated. Parathyroid hormone (PTH)(1?34) gene (179 bp) was inserted into a human cytomegalovirus promoter (PCMV) and E. coli competent cells were used to amplify the cDNA. Polymeric micelle formations (100 νl) formed from PCMV-PTH(1-34) cDNA (7.2 μg/μl) and 6% (w=v) polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) was administered at 8-hr intervals for 48 hr and then at 8-hr intervals for 24 hr weekly for 3 weeks. Parathyroidectomized rats receiving 150 μl of EDTA (10mM) before each dose of formation served as the study group; rats receiving drinking water, EDTA (10mM), PCMV-PTH(1?34) cDNA and PCMV-PTH(1?34) cDNA plus EDTA at the same amount and time intervals served as the control groups. Serum levels of calcium and PTH(1?34) were measured weekly for 4 weeks. Immunohistochemical stain for PTH(1?34), reverse transcriptase polymerase chain reaction for PTH(1?34) mRNA and the relative density of PTH(1?34) mRNA were performed at 2 and 4 weeks after oral gene therapy in different organs. One third to three of five rats in the control groups died after parathyroidectomy. Serum levels of calcium and PTH(1?34) were higher in the study than in the control groups. In the study group, positive stain of PTH(1?34) and PTH(1?34) mRNA could be found in those organs. Relative densities of PTH(1?34) mRNA were higher in the study than in the drinking water group in different organs. Oral gene therapy can maintain calcium and PTH(1?34) levels in parathyroidectomized rats.